Glass-ceramics and electronic components

Abstract

A glass-ceramic comprising a glass containing Si, B, Al and Zn and an aggregate, wherein the glass is contained in an amount of 45 to 80% by weight, and 20 to 50% by weight of SiO2, 20% by weight or less of Al2O3 and 10% by weight or less of ZnO are contained as the aggregate with respect to the weight of the glass-ceramic.

Description

Technical Field

[0001] This invention relates to glass ceramics and electronic components. Background Technology

[0002] As a ceramic material for ceramic multilayer wiring boards, glass-ceramic materials that can be calcined at low temperatures are known.

[0003] For example, Patent Document 1 discloses a glass composition for a low-temperature calcined substrate having a basic composition of RO-Al2O3-B2O3-SiO2 (wherein RO is selected from one or more of MgO, CaO, SrO, BaO, and ZnO), with RO and Al2O3 both in the range of 1 to 25 mol% and the mol% ratio of SiO2 / B2O3 being 1.3 or less, and a glass ceramic containing aggregate in the glass composition for the low-temperature calcined substrate.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-26529 Summary of the Invention

[0007] The glass-ceramic described in Patent Document 1 can achieve 20×10 at 3GHz. -4 The following is an example of excellent dielectric loss.

[0008] However, the SiO2 / B2O3 mol% ratio of the glass composition for low-temperature calcination substrates described in Patent Document 1 is less than 1.3, resulting in a high boron content. While such a high-boron glass composition can reduce dielectric loss, it suffers from unstable boron content. Specifically, the following problems exist: boron dissolves into the solvent during mixing and pulverization, or volatilizes during calcination. If the boron content decreases due to dissolution or volatilization, the viscosity of the glass decreases during calcination, leading to insufficient sintering. Furthermore, glass with reduced boron due to dissolution and volatilization exhibits unstable chemical properties and lower resistance to moisture and plating solutions, potentially resulting in reduced quality.

[0009] In addition, the glass-ceramic described in Patent Document 1 has a low coefficient of thermal expansion of less than 6ppm / K, which is significantly different from the coefficients of thermal expansion of other dielectrics and packaging substrates, and therefore is prone to causing poor quality.

[0010] The purpose of this invention is to solve the above-mentioned problems and provide a glass-ceramic with a relatively low permittivity and dielectric loss and a high coefficient of thermal expansion.

[0011] One embodiment of the glass-ceramic of the present invention is a glass-ceramic comprising a glass containing Si, B, Al and Zn and aggregates, comprising 45% to 80% by weight of the aforementioned glass, and comprising, relative to the weight of the aforementioned glass-ceramic, 20% to 50% by weight of SiO2, less than 20% by weight of Al2O3 and less than 10% by weight of ZnO as the aforementioned aggregates.

[0012] Another embodiment of the glass-ceramic of the present invention is a glass-ceramic containing Si, B, Al and Zn, wherein the SiO2 content is 52.00% to 71.58% by weight, the B2O3 content is 6.30% to 21.00% by weight, the Al2O3 content is 7.63% to 22.00% by weight, the ZnO content is 5.04% to 17.00% by weight, and the Li2O content is less than 0.55% by weight.

[0013] The electronic component of the present invention includes a glass-ceramic layer, wherein the glass-ceramic layer is a sintered body of the glass-ceramic of the present invention.

[0014] According to the present invention, it is possible to provide glass-ceramics with low relative permittivity and dielectric loss and high coefficient of thermal expansion. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view showing an example of a laminated ceramic electronic component, which is an electronic component of the present invention.

[0016] Figure 2 It is shown Figure 1 A schematic cross-sectional view of the stacked green blanks (uncalcined state) produced during the manufacturing process of the stacked ceramic electronic components. Detailed Implementation

[0017] The glass-ceramic and electronic components of the present invention will now be described. It should be noted that the present invention is not limited to the following configurations, and appropriate modifications can be made without departing from the spirit of the invention. Furthermore, combinations of multiple preferred configurations described below are also considered part of the present invention.

[0018] The glass-ceramic of this invention is a low-temperature co-fired ceramic (LTCC) material. In this specification, "low-temperature co-fired ceramic material" refers to a glass-ceramic material that can be sintered at a calcination temperature below 1000°C.

[0019] One embodiment of the glass ceramic of the present invention comprises: a glass containing Si, B, Al and Zn and aggregate, wherein the glass contains 45% to 80% by weight of glass, and, relative to the weight of the aforementioned glass ceramic, contains 20% to 50% by weight of SiO2, less than 20% by weight of Al2O3, and less than 10% by weight of ZnO as aggregate.

[0020] The glass used in this invention contains Si, B, Al and Zn.

[0021] As a glass, the preferred glass is one with a SiO2 content of 15% to 65% by weight, a B2O3 content of 11% to 30% by weight, a SiO2 to B2O3 weight ratio (SiO2 / B2O3) of 1.21 or higher, and an Al2O3 to ZnO weight ratio (Al2O3 / ZnO) of 0.75 to 1.64.

[0022] The SiO2 content in the glass is preferably 15% to 65% by weight, more preferably 45% to 60% by weight. When the SiO2 content is 15% to 65% by weight, it helps to reduce the relative permittivity during the sintering of the glass-ceramic containing the glass. As a result, parasitic capacitances and other factors associated with higher frequency electrical signals are suppressed.

[0023] If the SiO2 content in the glass exceeds 65% by weight, there are problems such as difficulty in sintering below 1000°C, or the crystallization temperature rising, making it difficult for ZnAl2O4 crystals to precipitate. In particular, since crystals do not precipitate during the calcination of glass ceramics when the crystallization temperature exceeds 1000°C, the Q value of the glass ceramic tends to decrease. On the other hand, if the SiO2 content in the glass is less than 15% by weight, the viscosity decreases excessively, making vitrification difficult.

[0024] B2O3 in glass contributes to a reduction in glass viscosity. As a result, the sintered body of glass-ceramics becomes denser.

[0025] The B2O3 content in the glass is preferably 11% to 30% by weight, more preferably 15% to 30% by weight.

[0026] Furthermore, the weight ratio of SiO2 to B2O3 (SiO2 / B2O3) is preferably 1.21 or higher. If the weight ratio is within this range, the proportion of B2O3 in the overall glass is relatively small. Therefore, it is less likely for boron to dissolve or volatilize from the glass, and it is less likely to cause problems such as insufficient sintering and reduced resistance to plating solutions.

[0027] In addition, the weight ratio of SiO2 to B2O3 (SiO2 / B2O3) is preferably 4 or less.

[0028] Al₂O₃ in glass helps improve its chemical stability. Additionally, ZnO in glass, together with Al₂O₃, forms the crystalline phase ZnAl₂O₄.

[0029] If the glass contains Al and Zn, ZnAl2O4 crystals, which contribute to low-loss precipitation, will precipitate in the glass.

[0030] The weight ratio of Al2O3 to ZnO (Al2O3 / ZnO) is preferably 0.75 to 1.64. If the above weight ratio is within this range, the content of ZnAl2O4 in the glass is within the preferred range.

[0031] If the weight ratio of Al2O3 to ZnO (Al2O3 / ZnO) is less than 0.75, there is too much ZnO, which will decrease the Q value, the reciprocal of dielectric loss. On the other hand, if the weight ratio of Al2O3 to ZnO (Al2O3 / ZnO) exceeds 1.64, there is too much Al2O3, which will increase the viscosity of the glass and sometimes make it impossible to obtain a dense sintered body.

[0032] In the glass-ceramic of the present invention, the glass is preferably a crystalline glass and contains ZnAl2O4, which is a crystalline phase precipitated from the glass.

[0033] Glass ceramics exhibit low dielectric loss and high Q value by precipitating ZnAl2O4 during calcination. Therefore, the crystallization temperature of the glass is preferably below the calcination temperature of the glass ceramic. Specifically, the crystallization temperature of the glass is preferably below 1000°C. If the crystallization temperature of the glass is below 1000°C, the Q value can be improved.

[0034] In the glass-ceramic of the present invention, the glass may contain Li₂O as a secondary component. The Li₂O content is preferably 1.0% by weight or less. Li₂O in the glass helps to reduce glass viscosity. The sinterability of the glass-ceramic is improved if the glass contains Li₂O.

[0035] The glass-ceramic of the present invention contains 20% to 50% by weight of SiO2 as aggregate.

[0036] Quartz is preferred as the SiO2 aggregate. Due to its low relative permittivity, quartz can reduce the relative permittivity of glass-ceramics when used as an aggregate. Furthermore, quartz contributes to increasing the coefficient of thermal expansion during the sintering of glass-ceramics. The coefficient of thermal expansion of glass is approximately 6 ppm / K, while that of quartz is approximately 15 ppm / K. Therefore, by including quartz in the glass-ceramic, a high coefficient of thermal expansion is obtained during sintering. Consequently, the difference in thermal expansion between the quartz and metallic materials such as Ag and Cu used as electrodes can be reduced, resulting in less thermal stress generated during cooling after sintering and reducing the likelihood of internal defects such as cracks around the electrodes.

[0037] Furthermore, reliability is improved when encapsulated on a packaging substrate (e.g., a resin substrate). However, if the amount of quartz added increases, there is a tendency for the Q value to decrease slightly.

[0038] If the SiO2 content as aggregate is 20% to 50% by weight, the coefficient of thermal expansion of the glass ceramic can be increased to approach that of conductive layers composed of copper, silver, etc. If the SiO2 content as aggregate is less than 20% by weight, the coefficient of thermal expansion of the glass ceramic may be too small. If the SiO2 content as aggregate exceeds 50% by weight, the coefficient of thermal expansion of the glass ceramic may become larger.

[0039] For SiO2 as aggregate, amorphous silica or silica glass can also be used. Amorphous silica and silica glass have a lower relative permittivity than quartz, thus further reducing the relative permittivity of glass-ceramics. Multiple types of quartz, amorphous silica, and silica glass can also be used.

[0040] The glass-ceramic of the present invention contains less than 20% by weight of Al2O3 as aggregate.

[0041] It should be noted that the glass ceramic of the present invention may also not contain Al2O3 as aggregate.

[0042] Al₂O₃, used as an aggregate, contributes to achieving low dielectric loss and high mechanical strength during the sintering of glass-ceramics. Specifically, the Q value increases by adding Al₂O₃. Furthermore, the flexural strength increases; by using Al₂O₃ as an aggregate, glass-ceramics with a flexural strength exceeding 150 MPa can be obtained. The flexural strength of glass-ceramics affects the strength when manufactured into electronic components, therefore, the higher the better. Especially preferred is 150 MPa or higher.

[0043] The increased flexural strength is due to the promotion of ZnAl2O4 precipitation from the glass by adding Al2O3 as aggregate. Additionally, it is due to the presence of Al2O3 as a crystalline phase, which has a high Q value and high strength.

[0044] Furthermore, the presence of Al2O3 as aggregate helps prevent the precipitation of cristobalite crystals during the sintering of the glass-ceramic. Although cristobalite is a type of SiO2 crystal, it undergoes a phase transition at approximately 280°C. Therefore, if cristobalite crystals precipitate during the sintering process of the glass-ceramic, the volume change at high temperatures will be significant, reducing reliability. From this perspective, it is preferable that the glass-ceramic does not contain cristobalite crystals. Here, "not containing cristobalite crystals" means that the content of cristobalite crystals is below the detection limit. The presence or absence of cristobalite crystal precipitation is confirmed by crystal structure analysis such as X-ray diffraction (XRD).

[0045] To achieve the aforementioned effects by including Al2O3 as an aggregate, the amount of Al2O3 added is preferably 1% by weight or more. However, the addition of Al2O3 increases the relative permittivity of the glass-ceramic. Therefore, the amount of Al2O3 added as an aggregate is preferably 10% by weight or less. Furthermore, if the amount of Al2O3 added as an aggregate exceeds 20% by weight, the sintering of the glass-ceramic is hindered.

[0046] The glass ceramic of the present invention contains less than 10% by weight of ZnO as aggregate.

[0047] It should be noted that the glass ceramic of the present invention can also be used as aggregate without containing ZnO.

[0048] If it contains ZnO as an aggregate, it can improve sinterability. In addition, it can replenish the volatile components of ZnO in the glass.

[0049] To achieve the aforementioned effects by including ZnO as an aggregate, the amount of ZnO added is preferably 1.0% by weight or more, more preferably 2.5% by weight or more. However, if the amount of ZnO added as an aggregate exceeds 10% by weight, the relative permittivity of the glass ceramic becomes higher. Furthermore, the addition of ZnO sometimes results in the formation of Zn₂SiO₄ (zinc silicate) during calcination.

[0050] The glass-ceramic of the present invention preferably contains SiO2, ZnAl2O4, and Al2O3 as crystalline phases. By including SiO2, ZnAl2O4, and Al2O3 as crystalline phases in the calcined glass-ceramic, it becomes a glass-ceramic with a relatively low permittivity, low dielectric loss, high Q value, high coefficient of thermal expansion, and high flexural strength. Quartz is preferred as the SiO2 crystalline phase, and zinc spinel (Gahnite) is preferred as the ZnAl2O4 crystalline phase.

[0051] These crystalline phases can be identified through crystal structure analysis, such as X-ray diffraction (XRD).

[0052] The relative permittivity of the glass-ceramic of the present invention is preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 4.3 or less.

[0053] The relative permittivity of glass ceramics is specified as the value measured at 6 GHz or 30 GHz.

[0054] The relative permittivity at 6 GHz can be determined using the perturbation method.

[0055] The relative permittivity at 30 GHz can be obtained using TE according to JIS R 1641. 011 The measurement was performed using the mode resonator method.

[0056] According to the present invention, a glass-ceramic with low boron content, low relative permittivity and dielectric loss, high Q value, and high coefficient of thermal expansion can be provided. Further inclusion of Al2O3 as aggregate can increase the Q value and improve flexural strength.

[0057] It should be noted that in the glass-ceramic of the present invention, the glass and aggregate can be distinguished or separated by using a scanning electron microscope (SEM) or a transmission electron microscope (TEM) to analyze the electron diffraction pattern, or by using hydrogen fluoride or the like to dissolve the glass portion.

[0058] By performing elemental analysis on the separated glass and aggregate using wavelength dispersive X-ray diffraction (WDX), energy-dispersive X-ray diffraction (EDX), and inductively coupled plasma atomic emission spectrometry (ICP), the composition of the glass and aggregate can be determined separately. Using these methods, the SiO2 content in the glass and the SiO2 content in the aggregate can be determined separately. The same applies to other elements.

[0059] Another embodiment of the glass-ceramic of the present invention is a glass-ceramic containing Si, B, Al and Zn, wherein the SiO2 content is 52.00% to 71.58% by weight, the B2O3 content is 6.30% to 21.00% by weight, the Al2O3 content is 7.63% to 22.00% by weight, the ZnO content is 5.04% to 17.00% by weight, and the Li2O content is less than 0.55% by weight.

[0060] In addition, the SiO2 content is preferably 60% by weight or more, the B2O3 content is preferably 15% by weight or less, the Al2O3 content is preferably 15% by weight or less, and the ZnO content is preferably 12% by weight or less.

[0061] Another embodiment of the glass-ceramic of the present invention corresponds to a portion of the glass-ceramic in one embodiment of the present invention, which specifies the contents of Si, B, Al, and Zn without distinguishing between glass and aggregate. Therefore, this other embodiment of the glass-ceramic of the present invention achieves the same effect as one embodiment of the present invention.

[0062] [Electronic Components]

[0063] The electronic component of the present invention includes a glass-ceramic layer, which is a sintered body of the glass-ceramic of the present invention.

[0064] Examples of electronic components of the present invention include: a laminate having a plurality of glass-ceramic layers that are sintered bodies of the glass-ceramic of the present invention; or a laminated ceramic electronic component having a laminated ceramic substrate using the laminate and a chip component mounted on the ceramic substrate.

[0065] The electronic components of the present invention have a low dielectric constant and low dielectric loss because they have a glass-ceramic layer that serves as the sintered body of the glass-ceramic of the present invention.

[0066] A laminate containing multiple glass-ceramic layers that are sintered bodies of the glass-ceramic of the present invention can be used, for example, in communication ceramic multilayer substrates and laminated dielectric filters.

[0067] The electronic components of the present invention are particularly suitable for use in the millimeter-wave frequency band due to their low relative permittivity and dielectric loss and high Q value.

[0068] The coefficient of thermal expansion of the glass-ceramic layer is preferably above 6 ppm / K.

[0069] The relative permittivity of the glass-ceramic layer is preferably 4.5 or less.

[0070] The Q value of the glass-ceramic layer is preferably above 800.

[0071] The flexural strength of the glass-ceramic layer is preferably above 150 MPa.

[0072] The electronic component of the present invention includes electrodes made of a metal containing Cu, wherein the Cu contained in the glass-ceramic layer is preferably 0.5% by weight or less when converted to CuO.

[0073] When Cu is used as an electrode, Cu diffuses from the electrode into the glass-ceramic. Sometimes, Cu diffused from the electrode can alter the sinterability of the glass-ceramic around the electrode, causing defects such as voids. Adding a small amount of CuO as aggregate to the glass-ceramic can prevent these defects. Cu can also be added in greater amounts than 0.5% by weight (equivalent to CuO), but this can easily lead to Cu precipitation within the glass-ceramic, potentially causing short circuits between electrodes when manufacturing electronic components.

[0074] Figure 1 This is a cross-sectional view schematically showing an example of a laminated ceramic electronic component, which is an electronic component of the present invention. Figure 1 As shown, electronic component 2 includes: multiple glass-ceramic layers 3 stacked together (in... Figure 1 The laminate consists of 5 layers (1 in the middle) and chip components 13 and 14 mounted on the laminate. The laminate 1 is also a laminated ceramic substrate.

[0075] The glass-ceramic layer 3 is a sintered body of the glass-ceramic material of the present invention. Therefore, the laminate 1 formed by stacking multiple glass-ceramic layers 3, and the electronic component 2 having a laminated ceramic substrate using the laminate 1 and chip components 13 and 14 mounted on the laminated ceramic substrate (laminated body 1), are all electronic components of the present invention. The composition of the multiple glass-ceramic layers 3 may be the same as each other or different from each other, but it is preferred that they are the same as each other.

[0076] The laminate 1 may further have a conductor layer. The conductor layer may constitute, for example, passive components such as capacitors and inductors, or connection wiring that carries out electrical connections between components. Such a conductor layer includes, for example, Figure 1 The conductor layers 9, 10, and 11 and the via conductor layer 12 are shown.

[0077] Conductor layers 9, 10, and 11, and via conductor layer 12, preferably contain Ag or Cu as the main component. Using such a low-resistance metal prevents signal propagation delays associated with higher frequency electrical signals. Furthermore, since the glass-ceramic of the present invention is used as the constituent material of the glass-ceramic layer 3, it can be co-fired with Ag and Cu.

[0078] The conductor layer 9 is disposed inside the laminate 1. Specifically, the conductor layer 9 is disposed at the interface between the glass-ceramic layers 3.

[0079] The conductor layer 10 is disposed on one of the main surfaces of the laminate 1.

[0080] Conductor layer 11 is disposed on another main surface of laminate 1.

[0081] The via conductor layer 12 is configured to penetrate the glass-ceramic layer 3, serving to electrically connect the conductor layers 9 to each other, or to electrically connect the conductor layers 9 and 10, or to electrically connect the conductor layers 9 and 11.

[0082] The laminate 1 can be manufactured, for example, as follows.

[0083] (A) Glass preparation

[0084] Glass is prepared by mixing SiO2, B2O3, Al2O3, and ZnO, along with optional by-products (such as Li2O), with a SiO2 content of 15% to 65% by weight, a B2O3 content of 11% to 30% by weight, a SiO2 to B2O3 weight ratio (SiO2 / B2O3) of 1.21 or higher, and an Al2O3 to ZnO weight ratio (Al2O3 / ZnO) of 0.75 to 1.64.

[0085] (B) Preparation of glass ceramics

[0086] The glass-ceramic of the present invention is prepared by mixing glass with SiO2, Al2O3 and ZnO as aggregates, and other aggregates (CuO, etc.) added as needed.

[0087] (C) Production of raw blanks

[0088] The glass-ceramic of the present invention is mixed with binders, plasticizers, etc., to prepare a ceramic slurry. Then, the ceramic slurry is formed on a substrate film (e.g., polyethylene terephthalate (PET) film) and dried to produce a green sheet.

[0089] (D) Fabrication of stacked green sheets

[0090] Stacked green sheets (uncalcined state) are produced by stacking green sheets. Figure 2 It is shown Figure 1 A schematic cross-sectional view of the stacked green blanks (unfired state) produced during the manufacturing process of stacked ceramic electronic components. (See diagram below.) Figure 2 As shown, the stacked green sheet 21 is composed of multiple stacked green sheets 22. Figure 2 The green sheet 22 is composed of 5 sheets. After calcination, the green sheet 22 becomes the glass-ceramic layer 3. A conductor layer containing conductor layers 9, 10, 11 and a via conductor layer 12 can be formed in the stacked green sheets 21. The conductor layer can be formed using conductive paste containing Ag or Cu by screen printing, photolithography, etc.

[0091] (E) Calcination of stacked green blanks

[0092] The stacked green blanks 21 were calcined. The result was as follows: Figure 1 The layered body 1 shown.

[0093] The calcination temperature of the stacked green sheet 21 is not particularly limited as long as it is the temperature at which the glass ceramic of the present invention constituting the green sheet 22 can be sintered; for example, it can be below 1000°C.

[0094] The calcination atmosphere of the stacked green sheet 21 is not particularly limited. When using materials that are not easily oxidized, such as Ag, an air atmosphere is preferred when using materials that are easily oxidized, such as Cu. When using materials that are easily oxidized, a low-oxygen atmosphere, such as a nitrogen atmosphere, is preferred. In addition, the calcination atmosphere of the stacked green sheet 21 can also be a reducing atmosphere.

[0095] It should be noted that the stacked green sheet 21 can be fired while being held in place by a constraining green sheet. The constraining green sheet contains inorganic materials (e.g., Al2O3) that are substantially non-sintering at the sintering temperature of the glass-ceramic of the present invention constituting the green sheet 22 as its main component. Therefore, the constraining green sheet functions to suppress shrinkage in the main surface direction of the stacked green sheet 21 during firing without shrinking. As a result, the dimensional accuracy of the resulting laminate 1 (particularly conductor layers 9, 10, 11 and via conductor layer 12) is improved.

[0096] Chip components 13 and 14 can be mounted in the laminate 1 in a state of being electrically connected to the conductor layer 10. Thus, an electronic component 2 having the laminate 1 is constituted.

[0097] Examples of chip components 13 and 14 include, for example, LC filters, capacitors, and inductors.

[0098] Electronic component 2 can be encapsulated in a package substrate (e.g., motherboard) in such a way that it is electrically connected through conductor layer 11.

[0099] Example

[0100] The following examples illustrate more specifically embodiments of the glass-ceramic and laminated ceramic electronic components of the present invention. It should be noted that the invention is not limited to these embodiments.

[0101] (A) Glass preparation

[0102] Glasses G1 to G8 (all in powder form) with the compositions shown in Table 1 were prepared using the following method. First, the glass raw material powders were mixed and placed in a Pt-Rh crucible, and melted at 1650°C for at least 6 hours in an air atmosphere. Then, the resulting melt was rapidly cooled to produce chopped glass. The chopped glass was then coarsely pulverized, and organic solvent and PSZ balls (diameter: 5 mm) were placed in a container and mixed using a ball mill. During ball milling, the pulverization time was adjusted to obtain glass powder with a central particle size of 1.5 μm. Here, "central particle size" refers to the central particle size D50 measured using laser diffraction and scattering.

[0103] [Determination of glass crystallization temperature]

[0104] The temperature of each glass was measured in the range of room temperature to 1000℃ using a differential scanning calorimeter DSC3300SA (manufactured by NETZSCH), and the temperature of the heating peak was taken as the crystallization temperature. The results are shown in Table 1.

[0105] [Table 1]

[0106]

[0107] (B) Production of raw blanks

[0108] Next, the glass and aggregate were placed in ethanol with the composition shown in Table 2 and mixed using a ball mill. Then, the binder solution dissolved in the organic solvent was mixed with the plasticizer to prepare a slurry. The slurry was then formed onto a PET film using a doctor blade and dried at 40°C to obtain a green sheet with a thickness of 25 micrometers.

[0109] It should be noted that in the aggregate, SiO2 is quartz with a central particle size of 1 μm, and Al2O3 is particles with a central particle size of 0.5 μm.

[0110] (C) Preparation and evaluation of test specimens for evaluation

[0111] (1) Relative permittivity and Q value (reciprocal of dielectric loss)

[0112] As a test specimen for evaluating the relative permittivity and Q value (reciprocal of dielectric loss) of glass ceramics, green sheets were cut into 78mm×58mm pieces and stacked in 30 layers. The pieces were placed in a mold, pressed together using a press, cut into 50mm×50mm pieces, and then calcined at 980℃ for 60 minutes in a reducing atmosphere.

[0113] The calcined laminates are shown in Table 2 as ceramics L1 to L29.

[0114] The ceramics L6, L7, L12, L13, and L21 marked with * in Table 2 are not laminates of glass-ceramics using the present invention.

[0115] For the calcined samples, the thickness was measured, and the relative permittivity and Q value (the reciprocal of dielectric loss) at 6 GHz were determined using the perturbation method. The relative permittivity and Q value were determined using the following instruments. It should be noted that a relative permittivity of 5.0 or less and a Q value of 500 or more are respectively evaluated as good.

[0116] [Measuring Apparatus and Conditions]

[0117] Network Analyzer: Keysight 8757D

[0118] Signal generator: Keysight Synthesized Sweeper 83751

[0119] Resonator: Custom-made fixture (Resonant frequency: 6GHz)

[0120] It should be noted that the network analyzer was connected to the signal generator to measure cable loss before the measurement. Additionally, the resonator was calibrated using a standard substrate (quartz, dielectric constant: 3.73, Q value: 4545 @ 6 GHz, thickness: 0.636 mm).

[0121] (2) Coefficient of thermal expansion α

[0122] For ceramics L1 to L29, the coefficient of thermal expansion α was determined using a Dilato meter TD5000SE (manufactured by NETZSCH) within a temperature range of room temperature to 600°C. A coefficient of thermal expansion α of 6.0 ppm / K or higher was considered good.

[0123] (3) Flexural strength

[0124] Three-point bending tests were conducted on ceramics L1 to L29 using Shimadzu's Autograph AGS-5kNX according to JISR1601.

[0125] (4) Determination of crystal phase

[0126] The calcined samples of ceramics L1 to L29 were pulverized into powder and analyzed by X-ray diffraction (XRD). The symbols of the XRD crystal phases shown in Table 2 are as follows: Q is SiO2 (quartz), G is ZnAl2O4 (zinc spinel), A is Al2O3, and W is Zn2SiO4 (zinc siliceous mineral).

[0127]

[0128] According to the results in Table 2, the laminate of glass-ceramic layers, which is the sintered body of the glass-ceramic of the present invention, has a low relative permittivity, a high Q value (low dielectric loss), and a large coefficient of thermal expansion.

[0129] L6 has a lower coefficient of thermal expansion α, which is attributed to the aggregate SiO2 content being less than 20% by weight. L7 is due to insufficient sintering, attributed to a glass content of less than 45% by weight and an aggregate SiO2 content exceeding 50% by weight.

[0130] L12 was also found to be under-sintered, which is believed to be due to the glass content being less than 45% by weight.

[0131] L13 was also due to insufficient sintering, which was believed to be caused by the fact that the Al2O3 in the aggregate exceeded 20% by weight.

[0132] L21 has a high relative permittivity and a low Q value. This is believed to be due to the ZnO content in the aggregate exceeding 10% by weight.

[0133] Containing Al2O3 as aggregate, the sinterable L3, L5, L6, L8-11, L14, L15, and L17-29 have a flexural strength exceeding 150 MPa, which is relatively high.

[0134] (5) Determination of dielectric properties in the millimeter wave band

[0135] Using TE according to JIS R 1641 011 The relative permittivity and Q-value (reciprocal of dielectric loss) of ceramics L1, L3, L5, and L14 in the millimeter-wave band (30 GHz) were determined using the modal resonant cavity method. The results are shown in Table 3.

[0136] [Table 3]

[0137]

[0138] According to the results shown in Table 3, each glass ceramic exhibits a low relative permittivity even at millimeter-wave frequencies (approximately 30 GHz), resulting in a high Q value. For use as electronic components in the millimeter-wave band, a relative permittivity of 4.5 or less and a Q value of 800 or more are more preferable. Thus, the glass ceramic of the present invention is a material suitable for electronic components in the millimeter-wave band.

[0139] It should be noted that another embodiment of the glass ceramic of the present invention is a glass ceramic in which the contents of Si, B, Al and Zn are specified without distinguishing between glass and aggregate in one embodiment of the glass ceramic. The ratio of each element in the glass ceramic in the above embodiment can be calculated based on the glass composition shown in Table 1 and the glass ceramic composition shown in Table 2.

[0140] Each element is represented in the form of oxides. For example, ceramic L3 contains: 70.0 wt% glass G1 and 25.0 wt% SiO2 and 5.0 wt% Al2O3 as aggregates. The amount of SiO2 in ceramic L3 is 70.0 × 59.4 / 100 + 25.0 = 66.58 wt%, since it is the sum of the amount contained in glass G1 and the amount of aggregates. Similarly, B2O3 is 70.0 × 18.8 / 100 = 13.16 wt%, Al2O3 is 70.0 × 10.9 / 100 + 5.0 = 12.63 wt%, and ZnO is 70.0 × 10.9 / 100 = 7.63 wt%. Examples of the ratios of elements in some glass ceramics calculated in this way are shown in Table 4.

[0141] Table 4

[0142]

[0143] As shown in Table 4, another embodiment of the glass ceramic of the present invention has a lower B2O3 content, thus reducing the likelihood of boron leaching from the calcined glass ceramic and minimizing the problem of reduced plating resistance. Furthermore, the higher SiO2 content and lower Al2O3 and ZnO content in the glass ceramic reduces the relative permittivity.

[0144] As a glass-ceramic material, it is preferable that SiO2 is 60% or more by weight, B2O3 is 15% or less by weight, Al2O3 is 15% or less by weight, and ZnO is 12% or less by weight. This allows the relative permittivity to be 5 or less, and further, 4.5 or less.

[0145] Symbol Explanation

[0146] 1-layer stack

[0147] 2 electronic components

[0148] 3 glass-ceramic layers

[0149] Conductor layers 9, 10, and 11

[0150] 12-hole conductor layer

[0151] 13, 14 chip components

[0152] 21-layer stacked green sheet

[0153] 22 green sheet

Claims

1. A glass-ceramic comprising a glass containing Si, B, Al and Zn, and aggregate. in, Contains 45% to 80% by weight of the glass. The glass-ceramic comprises, by weight, 20% to 50% SiO2, less than 20% Al2O3, and less than 10% ZnO as aggregates. Furthermore, it contains SiO2, ZnAl2O4, and Al2O3 as crystalline phases. The glass has a SiO2 content of 15% to 65% by weight, a B2O3 content of 11% to 30% by weight, a SiO2 to B2O3 weight ratio of 1.21 or higher, and an Al2O3 to ZnO weight ratio of 0.75 to 1.

64.

2. The glass-ceramic according to claim 1, wherein, It contains more than 1% by weight of Al2O3.

3. The glass-ceramic according to claim 2, wherein it contains more than 1% by weight of Al2O3 as aggregate.

4. The glass-ceramic according to claim 1, wherein, The crystalline phase contains quartz as SiO2.

5. The glass-ceramic according to claim 1, wherein, It does not contain MgO, CaO, SrO, or BaO.

6. The glass-ceramic according to claim 1, wherein, The glass is a crystal glass. Furthermore, it contains ZnAl2O4, which belongs to the crystalline phase precipitated from glass.

7. The glass-ceramic according to claim 1, wherein, The glass contains Li2O as a secondary component. The glass contains less than 1.0% by weight of Li2O.

8. The glass-ceramic according to claim 1, wherein, The crystallization temperature of the glass is below 1000℃.

9. The glass-ceramic according to claim 1, wherein, The relative permittivity is less than 5.

10. A glass-ceramic comprising Si, B, Al, and Zn, in, The SiO2 content is 52.00% to 71.58% by weight, the B2O3 content is 6.30% to 21.00% by weight, the Al2O3 content is 7.63% to 22.00% by weight, the ZnO content is 5.04% to 17.00% by weight, and the Li2O content is less than 0.55% by weight. Furthermore, it contains SiO2, ZnAl2O4 and Al2O3 as crystalline phases.

11. The glass-ceramic according to claim 10, wherein, The crystalline phase contains quartz as SiO2.

12. The glass-ceramic according to claim 10, wherein, It does not contain MgO, CaO, SrO, or BaO.

13. An electronic component comprising a glass-ceramic layer, wherein the glass-ceramic layer is a sintered body of the glass-ceramic as described in any one of claims 1 to 12.

14. The electronic component according to claim 13, wherein the electronic component comprises electrodes made of a metal containing Cu. Furthermore, the Cu content in the glass-ceramic layer is less than 0.5% by weight when converted to CuO.

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